The proposal review panels (PRPs) meet at the APS before each cycle (three times per year), to develop a consensus on the rating, comments, and recommended amount of time for each new proposal. The review criteria used are essentially those of the International Union of Pure and Applied Physics. Users see the final score, comments, and recommended time.

Prior to each PRP meeting, the panel chair electronically assigns two primary reviewers for each proposal. Primary reviewers are expected to read the assigned proposal and be prepared to lead discussion regarding its content. To facilitate efficient discussion, the primary reviewers are encouraged to enter preliminary comments and scores into the proposal system before the meeting. All reviewers are expected to be somewhat familiar with all proposals before the panel and to contribute to discussion of each proposal.

Full details about the review and allocation of general user proposals can be found in the APS Policy and Procedure for General User Beam Time.

Proposals for macromolecular crystallography (MX) are reviewed on a rolling basis. Each proposal is rated by two reviewers, and the individual scores are averaged. Users see the final score and any comments entered by each reviewer.

Proposals are assigned to reviewers by APS User Office staff, on the basis of areas of expertise self-identified by the reviewer. Reviews are completed online, through a link emailed to the reviewer. The review criteria are weighted and the individual scores and average are computed automatically.

Full details about the review and allocation of general user proposals can be found in the APS Policy and Procedure for General User Beam Time.